What is a PLC?
A PLC or Programmable Language Controller is a compact industrial computer designed to control a system process from one location. You may have heard of a PLC, but haven't quite grasped the concept. a PLC is like the brain of an industrial automation device. a PLC controller can perform a variety of tasks simultaneously with built-in I/O modules (inputs and outputs), rather than having multiple machines or workers managing different systems and devices. Programmable Logic Controllers are ubiquitous and heavily utilized in many industries. This article will take an in-depth look at the major components of PLCs, programming languages, types of PLCs, and future PLC systems.
Traffic light signals are a good example of a PLC application. No longer does someone have to read data and push buttons, there is now a PLC system that can control and monitor this function within a housing unit. If programmable logic controllers are a relatively new concept to you, it may be difficult to imagine the many types of PLC applications that may be around you. Other recognized PLC applications include automatic car washes, elevators, automatic doors, and amusement rides.
History of the PLC
To understand the uses of PLCs, we need to go back to the 1960s. Think transistor radios, Barbie dolls, Special Forces action figures, and Chevy Impala. The machine processes of this era were controlled through the use of electromechanical relays. We're not talking about a few relays either; these systems took up entire walls. However, the size of the relay-driven machines was not the only drawback.
Disadvantages of relay-powered machines:
- Hard wiring must be done in a very specific order.
- Time-consuming troubleshooting.
- Constant troubleshooting due to worn relay contacts.
- Rigorous maintenance schedule.
- Large and bulky.
- Changes involve rewiring the entire system.
It wasn't long before engineers began brainstorming solutions to these pain points. With the introduction of computerized control in industry, the first version of the PLC was developed. The invention of the programmable logic controller is credited to Richard Morley and his company Bedford and Associates.
The PLC Advantage
Richard and his team focused on ensuring that maintenance electricians and plant engineers could easily understand and use this new programmable controller. Naturally, the process took a lot of trial and error to get to a controller that solved all the previous pain points while still being user friendly. Ultimately, they were able to accomplish this goal with the MODICON 184.
Today, PLCs offer several advantages over hard-wired relays, including reliability, flexibility, cost-effectiveness, speed, better communications and advanced data processing capabilities. However, the most unique advantage of PLC systems is their ability to be reprogrammed. As a result, they are highly adaptable to changes in processes or the requirements of monitoring applications.
In addition, programmable logic controllers have a variety of diagnostic tools that help make troubleshooting easy, for example:
- Report Generation
- Fault logging
- Step-by-step program simulation
- Manual Run Input/Output
PLC Components
When you think of a PLC, you may think of a large device with lots of buttons and plug-ins, but in reality, PLC controllers are small, compact devices that integrate other hardware and software components. To understand a PLC system, it's best to divide the system into two main parts: the central processing unit (CPU) and the input/output (I/O) interface system.